1. Field of the Invention
The present invention relates to the field of human healthcare. More particularly, the present invention relates to efforts to relieve that cervical strain that occurs during sleep and results in stress to the entire spine. More particularly yet, the present invention is directed at such an end by supporting the neck of a person sleeping in the prone position. Most particularly, the present invention is a pillow with a shape that achieves this goal.
2. Prior Art
As chiropractors, osteopaths, and orthopedic surgeons well know, the human back in the great majority of individuals is subject to painful and often debilitating ailments, ailments that tend to increase in severity with age. It is also well known that many of these ailments arise from or are exacerbated by the activities engaged in by the sufferers. Although many of these activities are amenable to change so as to improve the health of the back, one of them is quite resistant to change—the “activity” of sleep. The manner is which the body is unconsciously arrayed during the hours that an individual is asleep can have immense influence on the back pain and infirmities experienced while he is awake.
As a category, the type of sleep that can contribute most strongly to spinal problems is prone sleep, that is, sleeping on one's stomach. Although the sufferers realize the harm that prone sleep causes, since they can feel it every morning upon arising, many people find it difficult to fall asleep in other positions. This means that they have to choose between restless, and even sleepless, nights, with the difficulties attendant thereto, and good sleep followed by a back that leaves them in pain all day. Consequently, there is a great need, by those who insist on prone sleep, for measures that will permit that sleep position while preventing the spinal stresses associated with it.
One aspect of prone sleep on a mattress that contributes to back problems is the tendency of the body to take on a “swayback” configuration, to the detriment of vertebral interactions. For most people, swayback can be minimized by experimenting with mattresses and other sleep surfaces until one is found that adequately supports the midriff so as to leave the mid-back in a more healthful alignment.
Not so easy to remedy is the problem arising from the neck twist that accompanies prone sleep. Unless one makes an arrangement, such as sleeping on a mattress with a ventilated, face-shaped hole in the mattress at the appropriate location, it is quite uncomfortable to lie with the face downward. This means that the head must be turned to one side or the other. This in turn involves rotation of the cervical spine which causes stress to be distributed throughout the entire spine. In discussing the problem, one tends to picture the twist arising because of the turning of the head while the torso remains fixed. However, it is also possible for the twist to increase or decrease because the torso twists while the head remains in a fixed orientation. Although one refers to the turning of the head, therefore, it should be recognized that it is the twist-angle between the head and torso that must be addressed, regardless of how it arises. It will do no good, for example, to hold the head in a fixed, comfortable position, only to have the twist angle increase to a damaging degree because of the torso turning while the subject is asleep.
In most sleeping configurations, the prone sleeper will have his or her head turned by 90 degrees from its straight-ahead orientation. As a measure of the stress that this places on the neck, most people are aware that once childhood is past it is almost impossible to turn the head this far in both directions, and that this is certainly true if there is not the assist provided by the body's inertia and the mattress surface. The strain and stress placed on the neck by sleeping with this 90-degree rotation is something that continues for many hours at a time, indeed, the length of a night's sleep for the prone sleeper. This cervical (neck) strain in turn causes hyperextension of the lumbar spine. Throughout the spine, the vertebral segments are far more adapted to compression and anterior-posterior motion than they are to rotation. (See, for example, BIOMECHANICS OF MUSCULOSKELETAL INJURY, by Gonza, E. R., and Harrington, I. L., Williams & Wilkins, publishers, Baltimore, 1982, p. 165.) Indeed, rotational stresses and strains can cause deformation and disruption of the posterior ligaments and joint capsules, resulting in dislocation. Furthermore, torsional (rotational) stresses such as those that may result from the head-turning normally associated with prone sleeping, can cause small circumferential tears in the disc such as appear at the onset of disc degenerations. As the lesion advances, these tears enlarge and coalesce, becoming radial tears that ultimately lead to disc herniation. In general, these rotation-caused lesions cause changes in the posterior joints and in the discs. (See, for example, CHIROPRACTIC MANAGEMENT OF SPINE RELATED DISORDERS, by Gatterman, M. I., Williams & Wilkins, publishers, Baltimore, 1990, pp. 35–36.)
In addition to the injuries described thus far, the neck twisting associated with traditional prone sleep can cause posterior-facet syndrome, which has been associated with chronic back pain. Etiological factors associated with this syndrome include hyperextension of the lumber spine. Posterior facet syndrome can cause a narrowing of the intervetebral disc space, resulting in nerve root compression, symptoms of which include as pain, motor weakness, muscle atrophy, and sensory loss (numbness and paraesthesia). (See, for example, op. cit., pp. 42 and 161.)
Previous attempts to address the neck-twist stress associated with prone sleep have been directed at requiring the face of the sleeper to be directed toward the sleeping surface. See, for example, Priester III et al., U.S. Pat. No. 6,047,420 issued Apr. 11, 2000, which discloses a three-part array, one of which accepts the forehead of the prone sleeper and supports it sufficiently far from the sleep surface that that there remains a space between the sleeper's face and that surface, in general the top side of a mattress. There are two other components to the array of Priester III et al., consisting of supports to be place on each side of the sleeper to prevent him or her from rolling over. This latter feature follows because the device of Priester III et al. Is directed at persons who need, for one reason or another to sleep in a prone position even though that might not be their choice. Another approach to providing a “special arrangement” to allow the prone sleeper's face to be directed at the mattress is taught by Cuddy, U.S. Pat. No. 6,412,127 B1 issued Jul. 2, 2002. The device of Cuddy comprises in part a “doughnut” pillow akin to what is often used by persons lying prone while receiving a massage. Other attempts to configure the sleeping body for comfort or safety include the system taught by Burpo, U.S. Pat. No. 3,811,140, issued May 21, 1974, and the maternal positioning system of Ferguson, U.S. Pat. No. 6,047,419. Issued Apr. 11, 2000. Neither of these systems is appropriate for addressing the problem presently under discussion. For example, the system of Burpo is directed at rigidly aligning the body of a supine patient and therefore has no need to establish the relative orientation of the head and torso. Furthermore, its structure—consisting of two similar interconnected wedges, one running along each side of the patient's body, sloping down toward the body—is such that it cannot address the problem presently under discussion. On the other hand, the system of Ferguson is directed toward supporting a pregnant woman lying on her side. It has a single wedge-shaped body piece on which the mid-section of the woman's midsection is to be supported, and a contoured, inclined pillow section designed to accept the cheek of the woman tilted slightly upward. The pillow section is removably attachable to the body piece, the attachment interface consisting of two matching triangular surfaces. Even if the separate components of the Ferguson system are used in a configuration not taught by Ferguson, they will not serve the purpose being address by the present invention. Although it is possible and even comfortable to rest one's cheek on the Ferguson pillow piece if one is lying on one's side this is not the case if one is lying on one's stomach.
Therefore, what is needed is a device or method that will allow the person who, from preference, habit, or necessity, sleeps in the prone position, to do so without enduring the spinal stress associated with the head being twisted with respect to the torso through the angle usually associated with this sleep position. What is further needed is such a device or method that does not require the sleeper's face to be directed straight down toward the surface on which he or she is sleeping.